The present invention relates to an apparatus for spraying of liquids. More particularly, the present invention is directed to a roadside spraying apparatus which minimizes atomization and resulting drift of sprayed herbicides or other liquids, mounted on a detachable frame fixed to a vehicle, and controllable by a vehicle operator by means of a control panel, used to regulate the flow of the liquids as well as the direction in which the liquids are sprayed.
Many state highway departments, counties and cities, have for several years been mechanically cutting undesirable weeds, grass and brush in their right-of-ways. However, while such cutting has been primarily accomplished by hand labor or mechanical means, it can be costly and time consuming. In order to minimize these problems, many publicly funded organizations have attempted to spray their right-of ways with herbicides that would control the undesirable plant growth.
Herbicides used primarily for control of broad leaf weeds and some unwanted grasses are used extensively on the right-of-way, leaving desirable grasses alive for erosion control. These herbicides, such as MSMA and 2-4-D, are termed selective since they do not kill the desirable grasses. Other herbicides used primarily for control of vegetation on shoulders and in the roadway are intended to kill all vegetation and hopefully prevent its regrowth for some period of time. Such herbicides are termed residuals. Other liquids, including fertilizers, may also be advantageously applied along a roadway; however, since application of liquid herbicides is more common, Applicant concentrates this discussion upon the application of herbicides.
Such application almost invariably involves spraying a liquid from an apparatus comprising some type of nozzle. As liquid is sprayed from a moving nozzle, it is generally applied to strip-like areas of ground called swaths. A swath, in this context, also refers to the spray pattern produced by the nozzle and applied to the corresponding strip of ground.
The equipment which has been used in the past for roadside spraying of herbicides has generally been of three common types. Handgun-type sprayers are still commonly used today for lack of anything with more versatility. Another common type of equipment comprises a long boom extending out from the side of the vehicle and across the right-of-way. An example of such a long boom is shown in U.S. Pat. No. 2,995,307, issued to J. J. McMahon. Another has been the use of an off-center nozzle mounted to the side of the truck. The use of the off-center nozzle is discussed further below.
The long-extending boom has been used widely because of its ability to reach 25 to 30 feet into the right-of-way. Some designs have provided the boom in sections to give the operator more flexibility as to where he could spray the herbicide. This has also allowed the operator to save chemicals. That type of unit, however, does not lend itself to many right-of-way applications because of hills, back slops and obstructions in the areas to be sprayed. Common obstructions including trees, bluffs, road signs and the like are a major problem. Furthermore, the extended boom is vulnerable to contact with such obstructions causing extensive down time and delays accompanied by losses in production. It is also very expensive to replace such booms.